Oral and rectal thermometers having a temperature range of from about 92.degree. to 106.degree. F. have been in use for many years for sensing the temperature of the human body. The use of oral thermometers with infants is particularly troublesome due to the difficulty of keeping such a thermometer in the baby's mouth under conditions and for a time sufficient to permit the inserted portion of the thermometer to reach ambient conditions therein, and thereby produce a reasonably accurate reading of the actual temperature of the subject being temperature sensed. Consequently, for newborns, rectal thermometers are generally used which are believed to cause discomfort, and again are somewhat difficult to use, although not as difficult as the use of oral thermometers.
Another form of temperature sensing devices is illustrated in U.S. Pat. No. 4,296,631 to Fergason. In U.S. Pat. No. 3,968,690 to Blouin et al, there is disclosed a pacifier assembly including a mercury thermometer device, however, the concomitant problem of glass and mercury are still present.
As infants age with concomitant cutting of teeth, the use of an oral thermometer becomes hazardous due to the possibility of breakage as well as greater awareness by the subjects to the foreign object. Generally, the use of a thermometer is to generate data as to the existence of abnormal temperature, i.e., a temperature above 98.6.degree. F., and not necessarily the number of .degree.F. above normal temperature to permit the institution of a corrective protocol for the subject exhibiting an above normal temperature. The use of a thermometer for a subject is generally initiated based upon observable side effects of an abnormal temperature, e.g. skin color, respiration, etc. as distinguished from any constantly observable or recognized phenomena.
In the aforementioned co-pending application U.S Ser. No. 351,107, here is disclosed a pacifier assembly including a spherical capsule of a liquid crystal material submerged in a liquid medium, such as glycerine, in the interior bulbous chamber of the pacifier assembly. The liquid crystal material is responsive to a temperature above about 100.degree. F. whereby the liquid crystal material changes color to visually indicate abnormal temperature condition of a mammal, and in particular a homo sapien, utilizing such a pacifier assembly. Since the spherical capsule is essentially free flowing within the chamber, the pacifier assembly may not accurately and rapidly sense an abnormal condition depending upon the relative position of the spherical capsule with in the pacifier assembly to the mammal during use. E.g., if the mammal is standing up-right and the pacifier assembly extends downwardly concomitant with intermediate use, the spherical capsule tends to be point positioned proximate the guard and thus the heat transfer rate of the liquid medium might not be sufficient to cause the liquid crystal material to clear under discontinious conditions of use.